Waters Technologies Corporation

Ta Instruments, Inc.

Waters Investments Limited

Ta Instruments-waters LLC

Consarc Composition

Robert L Danley

John W Schaefer

John R Reader, Jr

Kevin J Reed

Xiaoping Hu

Raymond J Roberts

Patrick Traini

Described is a zone box for a differential scanning calorimeter. The zone box includes sheets of thermocouple alloy disposed between thermally conductive electrical insulator layers. A thermocouple alloy wire is electrically coupled to each one of the thermocouple alloy sheets. In addition, a pure metal wire is electrically coupled to each one of the thermocouple alloy sheets to enable remote measurement of voltage differences between the different thermocouple alloy sheets. The high thermal conductivity of the electrical insulator layers substantially reduces any thermal gradients across the sheets and maintains the connections of the thermocouple alloy wires and pure metal wires to the sheets to be at substantially the same temperature. The zone box reduces temperature difference measurement errors that result from inhomogeneity in the thermocouple alloy wires and variable temperature distributions along the length of the wires.

Zone box for a differential scanning calorimeter

A heat flow rate measurement method for use with a differential scanning calorimeter sensor is provided. The method includes calculating a heat exchange between a plurality of sample containers and a reference container placed on a plurality of sample calorimeter units and a reference calorimeter unit, respectively, and determining a heat flow rate of samples within the sample containers using the calculated heat exchange between the plurality of sample containers and the reference container. A multiple sample differential scanning calorimeter sensor and calorimeter system are also provided.

Multiple sample differential scanning calorimeter

A method and a calorimeter system for reducing error in a measured sample heat flow rate due to interpan heat exchange are described. The method includes sensing a heat flow rate to or from a sample container placed on a sample calorimeter unit in a single sample differential scanning calorimeter sensor and sensing a reference heat flow rate to or from a reference container placed on a reference calorimeter unit of the single sample differential scanning calorimeter sensor. The temperature of the sample container and the temperature of the reference container are also sensed. An interpan heat exchange between the sample container and the reference container is determined. A sample heat flow rate having reduced error is determined based on the sensed heat flow rate from the sample container and the determined interpan heat exchange rate.

Heat flow rate determination for a single sample differential scanning calorimeter

A heat flow sensor for a heat flux differential scanning calorimeter comprising twin thermopiles. The thermopiles each comprise positive and negative thermocouple alloys and electrically insulating ceramic components. Diffusion bonding is used to form thermocouple junctions in the thermopiles between the positive and negative thermocouple elements, and to attach the thermocouple elements to the ceramic components.

Thermopile differential scanning calorimeter sensor

A dynamic mechanical analyzer and a sample fixture for a dynamic mechanical analyzer that attaches fixed clamps in the sample fixture to a rigid frame using mounts that are compliant in the direction perpendicular to the sample displacement but which at the same time are resistant to rotation about the transverse direction of the sample. The compliant mounts include a pair of flexures that are attached to each fixed clamp and to the frame of the sample fixture. In an embodiment, the pair of flexures are thin flat members such that each pair constitutes two parallel leaf springs. The flexures flex to allow the fixed clamps to move perpendicularly to the sample displacement, but at the same time prevent rotation of the fixed clamps.

Dynamic mechanical analyzer and sample fixtures for a dynamic mechanical analyzer

A method of operating a differential scanning calorimeter wherein errors in the heat flow rate measurement are reduced by operating the calorimeter in a quasiadiabatic mode and by employing a heat flow rate measurement algorithm that includes the leakage heat flow rate. The temperature of the DSC enclosure is controlled independently of the temperature of the measuring system, which allows the temperature difference between the sample and reference containers and the enclosure to be minimized, thus minimizing leakage heat flow.

Quasiadiabetic differential scanning calorimeter

A balance for a simultaneous differential thermal analysis instrument that combines gravimetric measurements with measurements that require propagation of electrical signals from the sample holder to an apparatus for recording the electrical signals. In one embodiment of the present invention, conductive cross-flexure pivots are used in a parallel guided balance to mechanically and electrically couple the components of the balance mechanism to the apparatus that records the electrical signals.

Simultaneous differential thermal analysis system

A balance for a simultaneous differential thermal analysis instrument that combines gravimetric measurements with measurements that require propagation of electrical signals from the sample holder to an apparatus for recording the electrical signals. In one embodiment of the invention, conductive flat planar strip flexure pivots are used in a single-meter movement balance to mechanically and electrically couple the components of the balance mechanism to the apparatus that records the electrical signals.

A cooling system employs a single-acting positive displacement bellows pump to transfer a cryogenic liquid such as liquid nitrogen from a storage dewar to a heat exchanger coupled to a measurement chamber of an instrument, wherein cooling takes place by vaporizing the liquid. Preferably, the capacity of the pump is greater than the maximum cooling requirement of the instrument, wherein both vapor resulting from vaporizing of the cryogenic liquid circulated through the heat exchanger and liquid that does not vaporize when circulated through the heat exchanger are returned to the storage dewar, wherein the vapor is subsequently vented from the dewar. Preferably, with the aid of a weir in a return line, the level of liquid in the heat exchanger is maintained full and constant, and the cooling demands are automatically met without the need for other control of the flow rate or level of the liquid. Also, unlike conventional systems, liquid transfer from the dewar does not require dewar pressurization, so that the dewar may be refilled whenever necessary without interrupting the experiment in progress.

Cooling system using positive displacement cryogenic liquid pump

A heat flux differential scanning calorimeter (DSC) is disclosed. The DSC can be configured with a highly conductive sample assembly enclosure. The enclosure can include a high emissivity coating. In one embodiment, the enclosure extends along a longitudinal direction that is about the same as that of an infrared lamp assembly used to heat the enclosure, thereby increasing the efficiency of heating the sample enclosure. In one embodiment, a gas-filled thermal resistor is used to couple the measurement assembly to a heat sink, such that samples can be rapidly heated and rapidly cooled.

Infrared heated differential scanning calorimeter

A thermal measurement apparatus and method for performing heat flux differential scanning calorimetry (DSC) is disclosed. A variable thermal resistor is used to couple a measurement assembly to a heat sink in the thermal measurement apparatus, such that samples can be rapidly heated and rapidly cooled. The apparatus can be configured with a highly conductive sample assembly enclosure. The enclosure can include a high emissivity coating. In one embodiment, the enclosure extends along a longitudinal direction that is about the same as that of an infrared lamp assembly used to heat the enclosure, thereby increasing the efficiency of heating the sample enclosure. In one configuration, the variable thermal resistor comprises a gap whose gas composition can be varied during a sample measurement to independently optimize sample heating and cooling rates.

System and method for thermal analysis using variable thermal resistance

Systems and methods for minimizing extraneous forces and calculating corrected weights of samples based on buoyancy factors for a thermogravimetric analyzer (TGA). The TGA includes a balance chamber and a furnace configured to heat a sample. A null balance is provided in the balance chamber and is used to measure the sample weight change during heating. The furnace includes a cylinder open at the top to receive a sample. The bottom of the cylinder is closed except for a small hole that allows a thermocouple to pass through. An infrared heat source may be provided to heat the cylinder. The balance chamber can be thermally isolated from the furnace using an actively cooled plate and a system of heat shields disposed between the furnace and balance chamber. A thermocouple disk is further provided to limit gas flow in the furnace and increase reliability of sample weight measurements.

System and method for a thermogravimetric analyzer having improved dynamic weight baseline

A sensor for a heat flux differential scanning calorimeter in which the differential temperatures are measured between locations external to the regions of heat exchange between the sensor and sample containers. The measured differential temperatures respond to the magnitude of the heat flow rate between the sensor and the sample and reference containers and are rendered insensitive to variations in the magnitude and distribution of thermal contact resistance between the sensor and the containers.

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Collingswood, NJ, United States of America

Robert L Danley